1. Field of the Invention
Aspects of the present invention relate to a monopolar direct liquid fuel cell used as an electric power for use with portable electronic appliances, and, more particularly, to a monopolar membrane-electrode assembly, in which a current collecting body is disposed on an upper portion or a lower portion of a catalyst layer.
2. Description of the Related Art
A direct methanol fuel cell (DMFC) generates electricity through a chemical reaction between methanol which is a fuel and oxygen which is an oxidizing agent and has high energy density and current density. The DMFC has advantages in that a periphery device, such as a fuel reformer, is not required since methanol is directly fed to the DMFC and storing and supplying of the liquid fuel may be performed easily.
A monopolar type DMFC may be manufactured to a relatively thin and small DMFC size since the thickness and volume of the DMFC may be reduced by connecting cells in series after a plurality of cells are arranged on one electrolyte sheet.
U.S. Pat. No. 6,410,180 discloses a mesh type current collector disposed on an electrode and a conductor that connects the current collectors. However, there is a step difference between the electrode and the current collector since the current collector is disposed on the electrode. Therefore, there is a risk of a leak of liquid fuel and a risk that the leaked liquid fuel may flow along the conductive material. Also, an efficiency of the DMFC may be reduced due to the increase in the contact resistance between the conductor and the electrode and the increase in the resistance that occurs while electrons generated in the catalyst layer migrate into the current collector through a fuel diffusion portion and a supporting member of the electrode.